<template>
  <span :style="{ color }">
    {{ value }}
  </span>
</template>
<script lang="ts">
import {
  defineComponent,
  ref,
  computed,
  watchEffect,
  unref,
  onMounted,
  watch,
} from 'vue'
import { useTransition, TransitionPresets } from '@admin/use'
import { isNumber } from '@admin/utils'

const props = {
  startVal: { type: Number, default: 0 },
  endVal: { type: Number, default: 2021 },
  duration: { type: Number, default: 1500 },
  autoplay: { type: Boolean, default: true },
  decimals: {
    type: Number,
    default: 0,
    validator(value: number) {
      return value >= 0
    },
  },
  prefix: { type: String, default: '' },
  suffix: { type: String, default: '' },
  separator: { type: String, default: ',' },
  decimal: { type: String, default: '.' },
  /**
   * font color
   */
  color: { type: String },
  /**
   * Turn on digital animation
   */
  useEasing: { type: Boolean, default: true },
  /**
   * Digital animation
   */
  transition: { type: String, default: 'linear' },
}

export default defineComponent({
  name: 'CountTo',
  props,
  emits: ['onStarted', 'onFinished'],
  setup(props, { emit }) {
    const source = ref(props.startVal)
    const disabled = ref(false)
    let outputValue = useTransition(source)

    const value = computed(() => formatNumber(unref(outputValue)))

    watchEffect(() => {
      source.value = props.startVal
    })

    watch([() => props.startVal, () => props.endVal], () => {
      if (props.autoplay) {
        start()
      }
    })

    onMounted(() => {
      props.autoplay && start()
    })

    function start() {
      run()
      source.value = props.endVal
    }

    function reset() {
      source.value = props.startVal
      run()
    }

    function run() {
      outputValue = useTransition(source, {
        disabled,
        duration: props.duration,
        onFinished: () => emit('onFinished'),
        onStarted: () => emit('onStarted'),
        ...(props.useEasing
          ? { transition: TransitionPresets[props.transition] }
          : {}),
      })
    }

    function formatNumber(num: number | string) {
      if (!num && num !== 0) {
        return ''
      }
      const { decimals, decimal, separator, suffix, prefix } = props
      num = Number(num).toFixed(decimals)
      num += ''

      const x = num.split('.')
      let x1 = x[0]
      const x2 = x.length > 1 ? decimal + x[1] : ''

      const rgx = /(\d+)(\d{3})/
      if (separator && !isNumber(separator)) {
        while (rgx.test(x1)) {
          x1 = x1.replace(rgx, '$1' + separator + '$2')
        }
      }
      return prefix + x1 + x2 + suffix
    }

    return { value, start, reset }
  },
})
</script>
